The Rosetta Nebula is a vast cloud of dust and gas, extending over an area of
more than 1 degree across, or about 5 times the area covered by the full moon.
Its parts have been assigned different NGC numbers: 2237, 2238, 2239, and 2246.
Within the nebula, open star cluster NGC 2244 is situated, consisted of the
young stars which recently formed from the nebula's material, and the brightest
of which make the nebula shine by exciting its atoms to emit radiation.
Star formation is still in progress in this vast cloud of interstellar
matter; a recent finding of a very young star with a Herbig-Haro type jet
by astronomers at the NOAO has been announced in
Press Release
NOAO 04-03 on January 22, 2004.

Although various values for its distance occur in the literature, our adopted
distance from the Sky Catalog 2000 implies a true diameter of the nebula of
about 130 light years. Burnham quotes a mass estimation of 10,000
(Minkowski 1949) to 11,000 (Menon 1962) solar masses, so it is one of the
more massive diffuse nebulae.

Open cluster NGC 2244 was discovered by Flamsteed about 1690. The nebula,
however, was not even seen by William Herschel (who found the cluster); its
different parts were discovered only by John Herschel (NGC 2239 = GC 1420 = h 392),
Marth (NGC 2238 = GC 5361 = Marth 99), and Swift (NGCs 2237 and 2246); note that
while now these numbers are used for describing parts of the diffuse nebula, their
original NGC description is quite different:

Nevertheless, the nebula is a splendid object, especially for astrophotography.

Our image was obtained by David Malin with the UK Schmidt Telescope.
This image is copyrighted and may be used for private purpose only.
For any other kind of use, including internet mirroring and storing on CD-ROM,
please contact the Photo Permissions Department (photo at aaoepp.aao.gov.au)
of the
Australian Astronomical Observatory.